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Abstract #21028 Published in IGR 10-2
Mitochondrial complex I defect induces ROS release and degeneration in trabecular meshwork cells of POAG patients: Protection by antioxidants
He Y; Leung KW; Zhang YH; Duan S; Zhong XF; Jiang RZ; Peng Z; Tombran-Tink J; Ge JInvestigative Ophthalmology and Visual Science 2008; 49: 1447-1458
PURPOSE: There is growing evidence that oxidative stress contributes to the progression of primary open-angle glaucoma (POAG), a leading cause of irreversible blindness worldwide. The authors provide evidence that mitochondrial dysfunction is a possible mechanism for the loss of trabecular meshwork (TM) cells in persons with POAG. METHODS: TM from patients with POAG (GTM) and age-matched subjects without disease (NTM) were obtained by standard surgical trabeculectomy. Primary TM cultures were treated with one of the following mitochondrial respiratory chain inhibitors: rotenone (ROT, complex I inhibitor), thenoyltrifluoroacetone (TTFA, complex II inhibitor), myxothiazol or antimycin A (MYX, AM-complex III inhibitors); mitochondrial permeability transition (MPT) inhibitor cyclosporine A (CsA); and antioxidants vitamin E (Vit E) or N-acetylcysteine (NAC). Mitochondrial function was determined by changes in mitochondrial membrane potential (DeltaPsim) and adenosine triphosphate (ATP) production with the fluorescent probes 5,5',6,6'-tetrachloro-1,1'3,3'-tetraethylbenzimid azolocarbocyanine iodide (JC-1) and a luciferin/luciferase-based ATP assay, respectively. Reactive oxygen species (ROS) level, determined by H(2)-DCF-DA, and cell death, measured by lactate dehydrogenase activity and Annexin V-FITC labeling, were also examined. RESULTS: GTM cells have higher endogenous ROS levels, lower ATP levels, and decreased DeltaPsim and they are more sensitive to mitochondrial complex I inhibition than their normal counterparts. ROT induces a further increase in ROS production, the release of cytochrome c, and decreases in ATP level and DeltaPsim in GTM cells, eventually leading to apoptosis. Complex II and III inhibition had little effect on the cells. Antioxidants protect against ROT-induced death by inhibiting ROS generation and cytochrome c release. CONCLUSIONS: The authors propose that a mitochondrial complex I defect is associated with the degeneration of TM cells in patients with POAG, and antioxidants and MPT inhibitors can reduce the progression of this condition.
Dr. Y. He, State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
Classification:
2.5.1 Trabecular meshwork (Part of: 2 Anatomical structures in glaucoma > 2.5 Meshwork)
3.7 Biochemistry (Part of: 3 Laboratory methods)
3.8 Pharmacology (Part of: 3 Laboratory methods)